joint state with sdf

#joint_state  

---

Table of Content

LAB

• load model SDF into ignition and rviz
• publish JointState from ignition to ros2 using bridge

├── CMakeLists.txt
├── config
│   └── rviz.rviz
├── launch
│   └── ign.launch.launch.py
│   └── ign_bridge.launch.py
├── models
│   └── vehicle_2
│       │   └── meshes
│       │       └── robot_base.stl
│       └── model.config
│       └── model.sdf
├── worlds
│   └── vehicle.sdf
└── package.xml

launch

ign

import os

from ament_index_python.packages import get_package_share_directory
from launch import LaunchDescription
from launch.actions import DeclareLaunchArgument
from launch.actions import IncludeLaunchDescription, SetEnvironmentVariable
from launch.conditions import IfCondition
from launch.launch_description_sources import PythonLaunchDescriptionSource
from launch.substitutions import LaunchConfiguration
from launch_ros.actions import Node

PACKAGE_NAME = "ign_tutorial"
SDF_MODEL_NAME = "vehicle_2"
WORLD_NAME = "vehicle.sdf"

def generate_launch_description():
    sim_time_arg = DeclareLaunchArgument(
        "use_sim_time",
        default_value=["true"],
        description="Enable sim time from /clock",
    )
    with_bridge_arg = DeclareLaunchArgument(
        "with_bridge",
        default_value=["false"],
        description="Launch simulation with ros ign bridge",
    )

    pkg_ros_gz_sim = get_package_share_directory("ros_gz_sim")
    pkg = get_package_share_directory(PACKAGE_NAME)

    sdf_path = f"{pkg}/models/{SDF_MODEL_NAME}/model.sdf"
    use_sim_time = LaunchConfiguration("use_sim_time")

    resources = [os.path.join(pkg, "worlds"), os.path.join(pkg, "models")]
    resource_env = SetEnvironmentVariable(
        name="IGN_GAZEBO_RESOURCE_PATH", value=":".join(resources)
    )

    gazebo = IncludeLaunchDescription(
        PythonLaunchDescriptionSource(
            os.path.join(pkg_ros_gz_sim, "launch", "gz_sim.launch.py")
        ),
        launch_arguments={"gz_args": f"-r -v 2 {WORLD_NAME}"}.items(),
    )

    # launch ign_bridge if with_bridge is true
    ign_bridge = IncludeLaunchDescription(
        PythonLaunchDescriptionSource(
            os.path.join(pkg, "launch", "ign_bridge.launch.py"),
        ),
        launch_arguments={"use_sim_time": use_sim_time}.items(),
        condition=IfCondition(LaunchConfiguration("with_bridge"))
    )

    # robot state publisher node
    robot_state_publisher = Node(
        package="robot_state_publisher",
        executable="robot_state_publisher",
        output="screen",
        parameters=[
            {"use_sim_time": use_sim_time},
            {"robot_description": open(sdf_path).read()},
        ],
    )

    ld = LaunchDescription()
    ld.add_action(sim_time_arg)
    ld.add_action(with_bridge_arg)

    ld.add_action(resource_env)
    ld.add_action(gazebo)
    ld.add_action(ign_bridge)
    ld.add_action(robot_state_publisher)
    return ld

bridge

from launch import LaunchDescription
from launch.actions import DeclareLaunchArgument
from launch.conditions import IfCondition
from launch.substitutions import LaunchConfiguration
from launch_ros.actions import Node

ROBOT_NAME = "basic_mobile_bot"

def generate_launch_description():
    use_sim_time_arg = DeclareLaunchArgument(
        "use_sim_time", default_value=["false"], description="use sim time from /clock"
    )

    namespace = ""
    use_sim_time = LaunchConfiguration("use_sim_time")
    ign_model_prefix = "/world/demo/model/" + ROBOT_NAME

    # clock bridge
    clock_bridge = Node(
        package="ros_gz_bridge",
        executable="parameter_bridge",
        namespace=namespace,
        name="clock_bridge",
        output="screen",
        arguments=["/clock@rosgraph_msgs/msg/Clock[ignition.msgs.Clock"],
        condition=IfCondition(use_sim_time),
    )

    # joint state bridge
    # /world/demo/model/v2/model/basic_mobile_bot/joint_state
    joint_state_bridge = Node(
        package="ros_gz_bridge",
        executable="parameter_bridge",
        namespace=namespace,
        name="joint_state_bridge",
        output="screen",
        parameters=[{"use_sim_time": use_sim_time}],
        arguments=[
            ign_model_prefix + "/joint_state"
            + "@sensor_msgs/msg/JointState"
            + "[ignition.msgs.Model"
        ],
        remappings=[(ign_model_prefix + "/joint_state", "/joint_states")],
    )

    ld = LaunchDescription()
    ld.add_action(use_sim_time_arg)
    ld.add_action(clock_bridge)
    ld.add_action(joint_state_bridge)
    return ld

tf tree

ros2 run rqt_tf_tree rqt_tf_tree

sdf

model

model

world

world

<include>
    <pose>0 0 1 0 0 0</pose>
    <uri>model://vehicle_2</uri>
</include>